CNS Development & Alcohol: Microglia-Neuron Interactions

描述(由申请人提供)：胎儿酒精综合症和相关疾病是导致智力低下的主要已知原因。了解产前酒精暴露的神经病理学是至关重要的。由于对酒精对神经元发育的干扰了解有限，目前尚缺乏预防酒精对胎儿大脑损伤的方法。为了解决这一知识差距，我们正在调查神经元-神经胶质相互作用在发育过程中酒精介导的神经毒性中的作用。小胶质细胞特别重要，因为它们提供神经元保护，或者在病理激活的情况下，介导神经元死亡。利用小脑颗粒细胞和小胶质细胞的共培养，我们发现小胶质细胞有效地保护神经元免受酒精中毒。我们使用活体新生大鼠模型进行的研究表明，单次酒精剂量会导致发育中的小脑中近40%的小胶质细胞丢失，存活的细胞似乎处于病理激活状态。培养中的研究表明，酒精诱导的小胶质细胞丢失是通过细胞凋亡发生的。因此，小胶质细胞群体的酒精缺乏可能会扰乱发育中大脑中小胶质细胞衍生的神经保护。有趣的是，我们的研究还显示，酒精降低了PPARGamma蛋白的水平，而且，PPARy的药理激活可以降低酒精对小胶质细胞和神经元的细胞毒性。 为了进一步研究这些发现，我们建议调查酒精破坏小胶质细胞-神经元相互作用的总体假设，包括诱导小胶质细胞凋亡、激活小胶质细胞和抑制小胶质细胞衍生的神经保护。体内和体外的互补模型将被用来检验这一假设。本提案的具体目的是：1.确定酒精诱导的发育中小脑小胶质细胞的丢失是否通过细胞凋亡来发生。2.确定酒精是否诱导存活的小胶质细胞群的激活。3.确定酒精对发育中的小胶质细胞的有害影响是否会破坏神经元和小胶质细胞之间的相互作用。4.确定酒精引起的小脑神经元和小胶质细胞的丢失是否涉及PPAR-γ信号的抑制，并可被PPAR-γ的激活所阻止。这项研究的结果将有助于更好地理解酒精对小胶质细胞和神经元之间关系的影响。这一知识的应用可能为干预产前酒精暴露引起的神经病理提供新的治疗策略。

DESCRIPTION (provided by applicant): Fetal alcohol syndrome and related disorders are the leading known cause of mental retardation. Understanding the neuropathology of prenatal alcohol exposure is critical. Methods for preventing alcohol associated brain damage in the fetus are lacking due to limited understanding of alcohol disruption of neuronal development. To address this gap in knowledge, we are investigating the role of neuronal-glial interactions in alcohol-mediated neurotoxicity during development. Microglia are uniquely important because they provide neuronal protection or, with pathologic activation, mediate neuronal death. Using co-cultures of cerebellar granule cells and microglia, we have found that microglia effectively protect neurons against alcohol toxicity. Our studies using an in vivo neonatal rat model reveal that a single alcohol dose produces almost 40% microglial loss in the developing cerebellum, and the surviving cells appear to be pathologically activated. Studies in culture suggest that alcohol-induced microglial loss is occurring by apoptosis. Thus, alcohol depletion of the microglial population may disrupt microglial-derived neuroprotection in the developing brain. Interestingly, our studies also reveal that alcohol reduces levels of the PPARgamma protein and, further, pharmacologic activation of PPARy can reduce alcohol cytotoxicity in microglia and neurons. To further these findings, we propose to investigate the overall hypothesis that alcohol disruption of microglial-neuronal interactions includes induction of microglial apoptosis, microglial activation, and suppression of microglial-derived neuroprotection. Complementary in vivo and in vitro models will be used to test this hypothesis. The specific aims of this proposal are to: 1. Determine whether alcohol-induced microglial cell loss in the developing cerebellum occurs by apoptosis. 2. Determine whether alcohol induces activation of the surviving microglial population. 3. Establish whether the deleterious effects of alcohol on developing microglia disrupt interactions between neurons and microglia. 4. Establish whether alcohol induced loss of neurons and microglia in the cerebellum involves suppression of PPARgamma, signaling and can be prevented by PPARgamma activation. Results of this study will provide better understanding of alcohol interference with the relationship between microglia and neurons. Application of this knowledge may provide new therapeutic strategies for intervention in the neuropathology caused by prenatal alcohol exposure.